Cyberattack cripples US (You mean you missed it?)

Organised by the Bipartisan Policy Center (BPC), the aim of the Cyber ShockWave exercise was to examine how the government could develop a real-time reponse to a large-scale cyber crisis.

The problem started with a downloadable application that infected smartphones. But it then spread to infect PCs, sending massive video files over the net and virtually shutting it down.

Later, two bombs disabled the country's electricity network and destroyed gas pipelines. The organisers even threw in a hurricane.

As the crisis developed, a group of security experts took the parts of senior politicians, debating their response.

Was there consititutional authority to shut down cellphone networks - or should the president just ask people nicely not to make calls?

Should the US fight back against the presumed attacker - rather quaintly, Russia?

Other actions included nationalising industries and rationing fuel.

A Washington hotel room was transformed into the White House Situation Room. In true Doctor Strangelove style, giant television screens displayed the unfolding crisis.

Officials taking part included Fran Townsend, former Homeland Security advisor to George W Bush. former deputy attorney general Jamie Gorelick and Charles Wald, a retired general and the former deputy commander of US European Command.

CNN's going to broadcast the whole thing at some point - which may have something to do with the inclusion of the bomb attacks, as it'll make much better telly that way. No aliens, though.